US2367595A

US2367595A - High temperature lamp

Info

Publication number: US2367595A
Application number: US429844A
Authority: US
Inventors: John W Marden
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1942-02-07
Filing date: 1942-02-07
Publication date: 1945-01-16
Anticipated expiration: 1962-01-16

Description

1945- J. w. MARDEN HIGH TEMPERATURE LAMP Filed Feb. 7, 1942 INVENTOR W W ATTORNEY Patented Jan. 16, 1945 HIGH TEMPERATURE LAMP John W. Marden, East Grange, N. 5., assignor to Westinghouse Electric & Manufacturing Company, East Pittsbur- Pennsylvania Pa, a corporation of Application February 7, 1942, Serial No. 429,844

9 (Claims.

This invention relates to electric, lamps and, more particularly, to such adapted to operate at very high temperatures by virtue of being formed,

at least in part, of material which will stand exceedingly high temperatures without fusing.

The principal object of my invention, generally considered, is the production of electric lamps formed, at least in part of material, more refractory than. quartz and having the ability to emciently transmit desired radiations.

Another object of my invention. is the production of electric discharge lamps adapted to oper-- ate with more intense arcs than have heretofore been possible in quartz, by virtue of being formed, at least in part, of a material such a fused magnesia or alumina which has a higher melting point than quartz.

further object of my invention is the production of electric discharge lamps consisting of envelopes of quartz or other suitable material with refractory, light-transmitting means between the electrodes, such as a liner formed of magnesia, for restricting the arc therebetween without at the same time melting or otherwise deteriorating.

A still further object of my invention is the provision of discharge lamps each having a bafile or [battles of refractory material, such as magnesium oxide, to thereby restrict and provide a more intense arc than is possible with the use of less refractory material, said lam-10s being adapted to produce radiations, not only from the discharge but from portions of the bafiie or baiiles' brought to incandescence.

An additional object of my invention is the provision of discharge lamps in which the intermediate portions are formed or refractory material such as fused, transparent magnesia in the form of tubes, the ends of said tubes being closed by the use of graded seals through which leads for the associated electrodes pass, said magnesia tubes desirably providing a constricted path for the discharge to thereby increase the intensity thereof to the desired point.

Other objects and advantages of the invention relating to the particular arrangement and construction of various parts, will become apparent as the description proceeds.

Referring to the drawing,

Fig. l is an axial sectional View of an electric discharge lamp formed with an envelope of quartz having a liner of magnesium oxide, or other similar refractory material, for restricting the discharge.

11-11 of Fig. 1 in the direction of the arrows.

Fig. 3 is a view corresponding to Fig. 1 showing a modification in which the envelope of the lamp is formed of quartz and a pair of bafiles of refractory material are provided, one adjacent each electrode.

Fig. e is a view corresponding to Fig. 3 but showing another form of my invention in which the entire central portion of the envelope is formed of refractory material such as fused magnesia and the end portions are graded therefrom to receive the lead-in conductors for the electrodes.

Fig. 5 is a view corresponding to Fig. 3 but showing another form of my invention in which only one balfie is used and the envelope is short so as to provide a point source of light.

Referring to the drawing in detail, and first considering the embodiment of my invention illustrated in Figs. 1 and 2, there is shown a discharge lamp ii consisting of an envelope l2 of quartz. The envelope is elongated and an intermediate portion thereof is part y closed by a liner it formed of material which efiiciently transmits the desired radiations, but which is more refractory, that is, has a considerably higher melting point than the material of the envelope it. The walls of the liner are, therefore, preferably thicker than those of the envelope. One of the most suitable materials for this purpose is pure fused, light-transmitting magnesia, which has a melting point of about -2800 0. Such material is a good transmitter, not only of visible light, but also of infra-red and ultra-violet radiations. At the same time it melts at such a high temperature that it may be brought to-incandescence and augment the light by the discharge without deterioration or change in shape. It may be finished, after rough forming from the fused condition, by machinery with specially hardened tools known in the art.

The lamp it may otherwise be constructed like a high intensity mercury discharge lamp, a globule of mercury being indicated at it. It is not necessary to have the entire envelope formed of magnesia because the hottest part will be where the liner i3 is positioned, and it is thereby possible to seal the lead-in conductors l5 and 5, having proper sealing characteristics, to the ends of the quartz envelope l2 for the support of the associated electrodes ii and It. The electrodes may be formed of tungsten or other similar material.

Referring now to the embodiment of my in- Fig. 2 is a traverse sectional view on the line vention illustrated in Fig. 3, the construction there disclosed is similar to that in Figs. 1 and 2, except that instead of a liner l3, the quartz envelope l2- of the lamp ll has a pair of bailies l9 and 2| formed of pure fused, light-transmitting, magnesia, like the liner l3 of the preceding embodiment, but shortened axially of the envelope and provided with restricted

apertures

22 and 23 therethrough for permitting a discharge of small diameter to pass between the electrodes ll' and i8. Otherwise the construction may be identical with that of Figs. 1 and 2.

Referring now to the embodiment of my invention illustrated in Fig. 4, there is shown a lamp ll having an envelope l2", the central or intermediate portion of which consists of a tube 24 having a small bore 25 and formed of pure fused, light-transmitting, magnesia like the liner 13 of Fig. 1. At the ends of this member 24,

quartz chambers

26 and 21 are provided for the associated electrodes ll and I8, the lead-in conductors 95 and I6" for said electrodes passing through the outer ends of

said chambers

26 and 21,

In order to make it possible to seal lead-in conductors of tungsten or other suitable lead material through the outer ends of said chambers, the lead-in receiving portions of the envelope I2 are connected to the magnesia intermediate part 24 by graded or stepped seals, that is, the composition of the material of the

chambers

26 and 21 may vary in expansion between the seal material through which the leads pass and magnesia, so that the

segments

28 and 29 are adapted to seal to the ends of the magnesia tube 24 without breaking. while the extreme portions 3| and 32 are adapted to permit the passage of the lead-in conductors Iii and IS without the formation of cracks. Otherwise, the construction of the lamp may correspond with that of known high-intensity mercury discharge lamps.

Referring now to the embodiment of my invention illustrated in Fig. 5, a lamp l I is here disclosed, which may be identical with the lamp H of the first embodiment, except that the liner 13 is shortened axially to be more like one of the bafiies l9 and 2! of the embodiment in Fig. 3, and the envelope I 2 is correspondingly shortened so that the lamp is adapted to act substantially as a point-source of light and thereby be suitable for projection and the like purposes.

Although I prefer the use of pure, fused, lighttransmitting magnesia for making the intermed ate discharge-engaging or restricting portions of the envelope, yet it will be understood that I do not wish to be limited to such material, as

pure, fused, light-transmitting alumina or other material having similar qualities, insofar as its endurance to heat and ability to transmit desired radiations is concerned, may be substituted, assuming that it may be formed into the necessary shapes or associated with a quartz or other suitable envelope for a discharge lamp.

From the foregoing description, it w ll be seen that I have devised an improved lamp particularly adapted for the production of an electric discharge of very much greater intensity than was heretofore possible, radiations of desired character being produced, not only by the discharge, but also by the incanuescence of the associated liner, baflie. or baffles. of the selected refractory material, which may serve to correct or modify the characteristics of the generated radiations. By virtue of the material selected. the lamp is adapted to efficiently produce and emit infra-red and ultra-violet radiations. as well as visible light.

It will also be understood that, except as here disclosed, suchlamps may be constructed like high-intensity discharge lamps in which the envelopes are quartz, that is the processes of exhausting, filling, and other handling during manufacture are similar to those employed in the manufacture of high-intensity mercury discharge lamps having quartz envelopes. Although preferred embodiments of my invention have been disclosed it will be understood that modifications may be made within the spirit and scope of the appended claims.

I claim:

1. An electric discharge lamp comprising an outer envelope formed in part of silicious material and in part of pure, fused, light-transmitting magnesia thicker than the silicious material, a plurality of electrodes therein, and leading-in conductors for said electrodes passing through said silicious material, that portion of the magnesia therebetween serving to direct and/or constrict an are when formed between said electrodes.

2. An electric discharge lamp comprising a generally cylindrical outer envelope formed of quartz, a pair of electrode therein, lead-in conductors for said electrodes passin through said quartz, and a plurality of magnesia baffles, corresponding in size with the interior diameter of the envelope and each having a relatively small central aperture, disposed between said electrodes for constricting the discharge therebetween.

3. An electric discharge lamp comprising a relatively short generally cylindrical outer envelope formed of silica, electrodes disposed therein and spaced relatively close to one another, and a bafiie of magnesia, corresponding in diameter with the bore of said envelope, provided with a small orifice, and disposed between said electrodes, whereby a discharge therebetween is constricted and a substantially point-source of light obtainable.

l. An electric discharge lamp comprising a generally cylindrical envelope formed in part of silicious material, and in part of a material of higher melting point than said silicious material and selected from the group consisting of pure, fused, light-transmitting materials more refractory than silica, a pair of electrodes therein, leadin conductors for said electrodes passing through said silicious material, and a plurality of baffles of said higher melting point material, corresponding in size with the interior diameter of the envelope, having relatively small central apertures, and disposed between said electrodes for constricting the discharge therebetween.

5. An electric discharge lamp comprising a relatively short generally cylindrical outer envelope formed in part of silicious material, and in part of a material of higher melting point than said silicious material and selected from the group consisting of pure, fused, light-transmitting materials more refractory than silica, electrodes disposed therein and spaced relatively close to one another, and a baffle of said higher melting point material, corresponding in diameter with the bore of said envelope, provided with an orifice relatively small as compared with said diameter, and disposed between said electrodes, whereby a discharge therebetween is constricted and a substantially point-source of light obtainable.

6. An electric discharge lamp comprising a generally cylindrical outer envelope formed of quartz, a pair of electrodes therein, lead-in conductors for said electrodes passing through said quartz.

and a plurality of alumina baflles, corresponding in size with the interior diameter of the envelope and each having a central aperture relatively small with respect to said diameter, disposed between said electrodes for constricting the discharge therebetween.

7. An electric discharge lamp comprising an outer envelope formed in part of silicious material, and in part of a material of higher melting point than said silicious material and selected from the group consisting of pure, fused, light-transmitting materials more refractory than silica, thicker than the silicious material, a plurality of electrodes therein, and lead-in conductors for said electrodes passing through said silicious material, that portion of the material of higher melting point therebetween serving to direct and/or constrict an are when formed between said electrodes.

8. An electric discharge lamp comprising an outer envelope formed in part of silicious material and in part of pure, fused, light-transmitting alumina thicker than the silicious material, a plurality of electrodes therein, and lead-in conductors for said electrodes passing through said silicious material, that portion of the alumina therebetween serving to direct and/or constrict an arc when formed between said electrodes.

9. An electric discharge lamp comprising a relatively short, generally cylindrical outer envelope formed of silica, electrodes disposed therein and spaced relatively close to one another, and a baffle of alumina corresponding in diameter with the bore of said envelope, provided with a small orifice, and disposed between said electrodes, whereby a discharge therebetween is constricted and a substantially point-source of light obtainable.

JOHN W. MARDEN.